[Presentation API] (5th) (1-UA) integrate controller and receiver side for 1-UA messaging

chrome/browser/media/router/browser_presentation_connection_proxy.h

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_MEDIA_ROUTER_BROWSER_PRESENTATION_CONNECTION_PROXY_H_
+#define CHROME_BROWSER_MEDIA_ROUTER_BROWSER_PRESENTATION_CONNECTION_PROXY_H_
+
+#include "content/public/browser/presentation_service_delegate.h"
+#include "content/public/common/presentation_session.h"
+#include "mojo/public/cpp/bindings/binding.h"
+
+namespace media_router {
+
+class MediaRouter;
+class MediaRoute;
+
+// This class represents a browser side PresentationConnection. It connects with
+// PresentationConnection owned by a render frame to enable message exchange.
+// Message received on this class is further routed to Media Router. State of
+// browser side PresentationConnection is always 'connected'.
+//
+// |SetTargetConnection| sets |target_connection_| to mojo handle of
+// PresentationConnection object owned a render frame, and transits state of
+// |target_connection_| to 'connected'.
+//
+// Send message from render frame to media router:
+// PresentationConnection::sendString();
+//     -> PresentationDispatcher::DoSendMessage();
+//         -> PresentationConnectionProxy::SendSessionMessage();
+//             --> (mojo call to browser side PresentationConnection)
+//                 -> BrowserPresentationConnectionProxy::OnMessage();
+//                      -> MediaRouter::SendRouteMessage();
+//
+// Instance of this class is only created for remotely rendered presentations.
+// It is owned by PresentationFrame. When PresentationFrame gets destroyed or
+// |route_| is closed or terminated, instance of this class will be destroyed.
+
+class BrowserPresentationConnectionProxy
+    : public NON_EXPORTED_BASE(blink::mojom::PresentationConnection) {
+ public:
+  using OnMessageCallback = base::Callback<void(bool)>;
+
+  BrowserPresentationConnectionProxy(const content::PresentationSessionInfo&,
+                                     MediaRouter* router,
+                                     const MediaRoute* route);
+  ~BrowserPresentationConnectionProxy() override;
+
+  void Bind(blink::mojom::PresentationConnectionRequest);

[mark a. foltz, 2017/01/27 18:30:05]

Outside of third_party/WebKit we the Media Router code has always been putting
parameter names (even when obvious).

Omitting parameter names is allowed by the style guide and I'm fine with it. But
I think it should be done consistently throughout a class definition.  So if you
want to do it here, suggest omitting |router|, |route|, |state| and |callback|
in this header as well.

[mark a. foltz, 2017/01/27 18:52:01]

Slight correction.   Parameter names can be omitted if they are unused.  Then
they should be commented out instead.  

Here's the full style guide entry.

https://google.github.io/styleguide/cppguide.html#Function_Declarations_and_D...

[zhaobin, 2017/01/27 22:11:40]

Acknowledged.

[zhaobin, 2017/01/27 22:11:40]

Adding them back.

+  void SetTargetConnection(blink::mojom::PresentationConnectionPtr connection);
+
+  // blink::mojom::PresentationConnection implementation
+  void OnMessage(blink::mojom::ConnectionMessagePtr message,
+                 const OnMessageCallback& callback) override;
+  void DidChangeState(
+      blink::mojom::PresentationConnectionState state) override {}
+
+ private:
+  content::PresentationSessionInfo session_info_;

[mark a. foltz, 2017/01/27 18:30:05]

The PresentationSessionInfo passed here only seems to be used in a debug logging
statement.  Is it necessary for this class?

If you need to keep it, then please declare as const.

[zhaobin, 2017/01/27 22:11:40]

Removed.

+
+  // |router_| not owned by this class.
+  MediaRouter* router_;
+  // |route_| not owned by this class.
+  const MediaRoute* route_;
+
+  mojo::Binding<blink::mojom::PresentationConnection> binding_;
+  blink::mojom::PresentationConnectionPtr target_connection_;
+};
+
+}  // namespace media_router
+
+#endif  // CHROME_BROWSER_MEDIA_ROUTER_BROWSER_PRESENTATION_CONNECTION_PROXY_H_